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Venus as the Moon

TKalbfus

SOC-14 1K
Venus as the Moon
This is an idea I’ve had, what if the Solar System formed differently with the result of the planet Venus taking the place of our Moon in orbit around Earth and our Moon taking its position in Venus’s orbit? To make it so that Venus doesn’t dominate our skies nor tidally lock itself or the Earth, I’m removing this satellite to an orbital diameter of 1,300,832 km, instead of the Moon’s distance of 384,400 km. This changes the length of a lunar month from 27.322 days to 170.87 days with about 2.14 months per year. I’ve checked this orbit and it seems that the attraction between Venus and Earth is greater than the difference in attraction between the Sun and Venus when it is closest to the Sun in its orbit about Earth and when its farthest away in that same orbit. You want numbers? Ok, the gravitational pull of Earth at 1,300,832 km is 0.000024 g and the difference in gravitational pull of the Sun at the distances of 148,699,168 km and 151,300,832 km is 0.000021 g and this does not take into account the gravitational pull of Venus on Earth, its seems that although this orbit is extreme, it is orbitally possible.

Another consideration is the tides of our new satellite, Our moon exerts a difference of gravitational force between the Earth’s nearside and far side of about 0.00000022 g, replace the Moon at about 384,400 km with Venus at 1,300,832 km and we get a difference of gravitational forces of about 0.00000038 g, in other words the tides would be 173% of what they are now, and high tide would be 173% of what we experience now, this is not too bad and civilization can adjust. As for the length of day, on Earth it remains 24 hours; on Venus I’ll substitute the value obtained by Jean-Dominique Cassini in 1666 of 23 hours and 21 minutes.

Venus appears in our skies as a blue-white disk of the same apparent diameter as our Sun or the Moon, it goes through phases similar to the Moon but it is also seen rotating. A complete cycle of phases takes about a year because a complete revolution of Venus around Earth takes an amount of time equal to half a revolution of the Earth around the Sun. In this altered Earth’s History, the year is not split into months. Instead the date is simply the year plus a number of days, or substituting for months we could use the signs of the Zodiac. When the Sun appears in a certain constellation in our sky that indicates what time of year it is, there are 12 Zodiac constellations and so on this Earth Astrology was more influential in the formation of the calendar than in ours. A ‘sign’ is a period of time roughly equivalent to a month with a variable number of days. So instead of saying its, May 3, 2005, you might say Aquarius 3, 2005 or whatever. The Zodiac sign indicates what time of the year it is, and gives people an idea of what the season is.

The Constellations of the year are as follows: Winter Gemini (31 days), Cancer(28 days, 29 on leap years), Leo (31 days); Spring Virgo(30 days), Libra (31 days), Scorpius (30 days); Summer Sagittarius (31 days), Capricorn (31 days), Aquarius (30 days); Autumn Pisces (31 days), Aries (30 days), Taurus (31 days). Unlike Our calendar, this calendar ends its year in late fall rather than in winter. New Years day comes before Christmas and Traditionally Christmas is celebrated on Gemini 8th, however the Russian Orthadox Church celebrates it on Gemini 25th.

History has preceded much like it did in our universe, the continents are in the same places as are the borders between nations. The fact that the ‘Moon’ is blue, has oceans and an atmosphere with clouds has attracted the imaginations of astronomers and science fiction writers. Some time in the late 1940s a V2 Rocket was launched above the atmosphere and a spectrographic analysis was taken of the “Moon’s” atmosphere and it was confirmed to have an atmosphere much like Earths. Ground based telescopes have confirmed the existence of rivers and vegetation on its surface. Radio communication was attempted with the ‘Moon’, but no response ever came other than a radar echo. The arrangement of continents on Venus are the same as on the real Venus, except that there are oceans filling all regions below the 0 km mean elevation datum. Typically take a map of the real Venus and everything you see that is green or blue is covered with water. Two main continents dominate the planet, those are Ishtar and the equator straddling Aphrodite. A lot of smaller land masses also dot the oceans. In 1957 Sputnik was launched and President Kennedy later announced his decision to land a Man on the Moon before this decade is out, and the Apollo program had begun. The main problem was that while a rocket capable of delivering people to the Moons surface was possible, bringing the astronauts safely back to the Earth was out of the question for chemical rockets such as the Saturn V. The solution was helped by two things, the first was the Moon’s Earthlike environment, and the second was the public fears about astronauts bring back deadly diseases obviously these was life on Venus, whether it was a danger to humans was yet to be determined. The solution was simple, don’t worry about bringing the Astronauts back, send them over and keep them resupplied by further rockets as necessary, eventually the Nerva Nuclear Rocket engine will be developed and will be capable of bringing them back to Earth, but the important thing was to beat the Soviets to the Moon. Surveyor probes were sent, and those that reached its surface sent back pictures of alien plant life although plant life with green leaves and so forth. Rovers tend to get bogged down after a time unless they are in deserts or in high artic regions, weather proves to be a problem for the long term survivability of remote controlled probes.

Apollo 11 is now on the Launch Pad, its 1969 and the huge moonship takes of from the launch pad 39a. There is no Moon lander. Instead there is an enlarged Apollo Capsule with Heat Shields and parachute with additional mass devoted to landing rockets so a touch down on solid ground can be achieved.

Now I ask the audience, how would you design such a mission? Would you have more than 3 astronauts onboard? Since the mission does not call for a return to Earth, the additional mass that would otherwise be used for the return stages can be devoted instead to the landing capsule. What would you bring, keeping it limited to TL 7 of course?
 
If it's just a race to put the first bootprints on Venus, I'd go with 2 men, a ground vehicle, basic survival equipment and the gear needed to establish multiple television transmitter sites.

If you want to do more meaningful exploration, send 4 men with 2 remaining in Venusian orbit on a Skylab-type station to conduct orbital survey and mapping.

I've always heard that if the first Mars landers has sent back photos of a palm tree, we'd have sent people there already. ;)

With a destination as attractive as your Venus, I'd use a much larger mission, something based on Von Braun's Mars mission plans. See here , here and here.
 
Of course that would be harder and perhaps take longer. The first objective would be to get there before the Soviets and prevent them from claiming the planet as a Soviet Territory. In some ways its likely that the life on this planet is similar to life on Earth as asteroid impacts will from time to time throw chunks of Venus to Earth and Earth to Venus given their close proximity, its also possible that the astronauts could try to grow their own food. We've established that there are no intelligent Venusians willing to have radio contact with Earth, but their could still be intelligent Venusians who don't use radio, either because they are savages or for other reasons. Whether they are friendly to the astronauts is an open question. The next step would be to generate detailed encounter tables for each type of terrain. Also the Soviets in this case aren't likely to give up, just because they didn't get their first, things could get quite interesting when the Soviets finally build a rocket that doesn't explode on the launch pad and send cosmonauts to Venus. The prize is just to valuable to abandon easily. Likely despite the Vietnam war, money would likely be found to continue the Apollo program and the Soviet competition to it. Figure from 1969 to 1972, NASA will send a total of 18 astronauts to the surface of Venus, possible as much as 24. By 1976 they'll send another 24, and 24 more by 1980. Figure on a small village by 1980, 72 more people by 1990 and some of the first astronauts will have had children by that time. A similar number of Cosmonauts will likely be sent. In total about 300 people might be living on Venus by 1990.
Anti-nuke people may have nixed the Nerva rocket by this time, so the Astronauts and their children still can't leave. NASA and the CCCP can still keep sending them stuff, but they can't yet bring them back, and we have't yet considered what dangers might lurk on the surface of Venus.
 
With a 'moon' that size, that close (relatively), and that habitable (his Venus is nothing like the real Venus supposedly) the space race is utterly different. You don't have the USSR launching Sputnik as a propaganda ploy in the late 50s and Kennedy taking the bait that Eisenhower wouldn't(1). Instead, you have an entirely different and earlier space race. With that sort of 'moon' hanging overhead, the first 'moon' mission won't be launched by the USA from Florida in 1969.

Surf on over to www.alternatehistory.com and use the search function to read some examples.

H. Beam Piper, a Traveller author before there was Traveller, left behind some notes for a book with this idea. Michael Kurland finished that project. It's called First Cycle. While the astrography is slightly different; the two planets are tidally locked to each other and thus revolve around a common point, the ideas in the book are very good. One planet launches a mission to the other as soon as it a marginally possible. Having another living world literally hanging overhead is a central part of both worlds' development.

The same would be true for an Earth with a 'Venus' less than 2 million miles off.


Have fun,
Bill

1 - The NASA/USAF X-plane projects of the 50s had put men in suborbital flight paths well before Gugarin went aloft as 'spam in a commie can'. The X-plane pilots even retroactively recieved astronaut wings in the mid-60s with little fanfare. A large part of NASA's 'tardiness' in 'answering' the Gurgarin flight was because NASA chose to abandon the X-plane model for the ballistic missile model, something that the USSR was hoping for. NASA and the US ditched years of X-plane flight research, quickly 're-invented' space flight along the USSR ballistic missile model, and still beat the commies to the Moon. Sadly along the way, beating the commies to the moon became NASA's only job and, when that was accomplished, the agency that had become little more than a clutch of public relations hacks lost it's way. However stirring it may have been for those who watched the speech, Kennedy's rash and asinine pledge to get to the Moon within a decade throttled the real US space program in its cradle.
 
Hoo boy.

OK, "Venus" is still able to orbit Earth at a distance of 1.3 million km. JUST. 200,000 km more and it's beyond Earth's Hill Sphere, and it orbits the sun instead. As it is, it's probably going to be very significantly perturbed by solar tides, being close to the edge of the Hill Sphere. It's almost certainly going to be orbiting in the solar system's ecliptic plane, not in earth's equatorial plane, so it will be an inclined orbit relative to Earth's equator.

The equilibrium tides raised on Earth by Venus alone are going to be about 0.61m high. The solar tide will be another 0.16m on top of that. The equilibrium tides raised by Luna on Earth are 0.36m high, so the tides raised by Venus alone will be 1.7 times higher than the current lunar ones (and that's not counting regional focussing, bays, etc).

However, "Venus" will also be tidelocked to Earth. In fact because they're very simliar in mass, I think Earth will be tidelocked to Venus too (like Pluto/Charon are to eachother) - not only will Venus' rotation period be equal to its orbital period, but Earth's rotation period will be slowed down to equal Venus' orbital period. So they hang over the same spot on eachothers' surfaces, and they both complete a rotation relative to the sun every 170.9 days. At the very least, Earth's rotation period will be significantly slower than 24 hours.

Even without that, Venus is still tidelocked to Earth. That means its 'day' is 170 days long. And that means its dayside would roast and its nightside would freeze... unless it had a superdense atmosphere to trap the heat like it does now, in which case all of it would roast like it does now.

On top of that, if they are totally sync-locked, then solar tides will act on the 'double planet' systems to start moving Venus TOWARD Earth. This will ultimately end up in a collision, resulting in the destruction of both Earth and Venus, possibly before the current age of the solar system has passed.

In short, it doesn't look like it's all that possible....
 
^ Spoil sport ;)

Just reading the set up, I can see natural history changing so significantly that there wouldn't be a humanity to plan a rocket trip to the new moon.

If tidally locked, the chance of chance of primitive life developing in tidal pools drops dramatically. Without tides, the chance of amphibians developing drop off too. In this scenario, the dominant life form of Earth after 5 billion years may still be protozoa or blue-green algea. And life on the new moon wouldn't fair much better.

Think about how much biochemistry is regulated externally by the lunar cycle. If it's that important now, think of its potential signficance in the past.

Something as insignificant as the human reproductive cycle; if it went from 12 times a year to just 2 or even 1, like most mammals. How might that have affected human history? No Kennedy? No Communism? No European culture? No Roman Empire? No fertile crescent? No Cro-Magnon? No Homo Erectus? How much reverse temporal damage can we do with one little change like the size of the moon?

This is just one small change to our environment due to the presence of a large satellite. What about the climactic changes associated with a moon of this size? Would temperature cycles be accentuated or attenuated? What about the affects of that much reflected light on animal behavior? So many interesting questions could be asked.

Anyway, it is fun to think about dramatic changes like this; please keep up the public day dreaming! And don't let party poopers like Mal get you down ;) He's just a stickler for realism, blah!
 
Venus doesn't so much orbit the Earth as both planets orbit each others common center of mass. Now why would Venus be tide locked to Earth and not Earth to Venus? Either they both are or they both are not. Now you admit that the tidal forces experienced by Earth are only 1.7 time that experienced by the Earth now due to the lunar tide. Remember that the Earth is not tidally locked to the Moon, how do you know that 70% more tidal force will be sufficient to lock the Earth? Maybe not. Ok, remember that our Moon experiences a much greater tidal force from Earth at its present distance than the Earth does from the Moon, so the Moon is tidal locked at its current distance. Venus is not placed at the Lunar distance, but at 1.3 million km. So I'm assuming that 70% more tidal force is not sufficient to tidal lock the Earth, not one must remember that since Venus and Earth are so similar in Mass that what Earth experiences in tidal forces from Venus is similar to what Venus experiences in tidal forces from Earth, so if the tidal forces aren't sufficient to lock the Earth, they are likely also insufficient to lock Venus as well. Yes, I know that most moons are tidally locked with their parent body, but Venus in this instance would make a most unusual moon, it would more accurately be described as a coplanet with Earth. It would most likely have formed out of the same cloud that formed the Earth, rather than being the result of a collision, an improbably event, but not an impossible one. Venus since it spins would also have a magnetic field. If Venus orbits along the plane of the ecliptic then once a year, some part of Earth would experience a total eclipse of the sun and once a year some part of Venus would also experience a total eclipse of the sun.
 
Besides, my purpose isn't so much to disagree with Malenfant as to have a planet with life on it that can be explored by TL 7 Explorers. I think this fits the bill nicely. I keep Earth relitively familiar. I keep Venus with the same geophysical features, add oceans and life to it. Then I want to open it up. The T20 Handbook has a section on it for generating animal encounters. I want to eventually have a set of animal encounter table with 20 entries for each terrain type, focusing mainly on the two continents Ishtar Terra, and Aphrodite Terra. The Climate of Ishtar is alot like Canada. The climate of Aphrodite ranges from tropical to temperate, (as in the lower 48 states of the US) The telperate parts of Aphrodite Terra are in the southern hemisphere and to me that seems like an ideal location for the first human base. I'm going to assume that Venus orbits in the equatorial plane and has a similar axial tilt to the Earth.

Since Venus is in the same Orbit as the Earth, its year is the same as the Earth, but since it's day is shorter there are 375.16 Venusian days in a year, about every 7th year would be a leap year, with the normal year being 375 days long on the Venusian calendar and the leap year being 376 days long.

There that should get us started.
 
Are you envisioning totally alien life forms or ones basically similar to those here with cosmetic differences?

Even starting with the same genetic stock you have a lot of room for diversity. A different ending to Earth's Cambrian period might have produced radically different life here.

Check out info on the Burgess Shale if you're not already familiar with it.
And depending on which (if any) extinction theories you follow, you could use our bio-history and move it several million years in either direction.
 
Originally posted by Tom Kalbfus:
[QB] Venus doesn't so much orbit the Earth as both planets orbit each others common center of mass. Now why would Venus be tide locked to Earth and not Earth to Venus? Either they both are or they both are not.
Yes, which is why it's likely they would be tidelocked to eachother.


Now you admit that the tidal forces experienced by Earth are only 1.7 time that experienced by the Earth now due to the lunar tide. Remember that the Earth is not tidally locked to the Moon, how do you know that 70% more tidal force will be sufficient to lock the Earth?
Because I've got equations in a Solar System Dynamics book that say that will be the case
.


if the tidal forces aren't sufficient to lock the Earth, they are likely also insufficient to lock Venus as well.
Well, they're sufficient to lock Venus, which is why I said they're probably sufficient to lock Earth too...


Yes, I know that most moons are tidally locked with their parent body, but Venus in this instance would make a most unusual moon, it would more accurately be described as a coplanet with Earth. It would most likely have formed out of the same cloud that formed the Earth, rather than being the result of a collision, an improbably event, but not an impossible one.
Right, but again, double planets are tidally locked to eachother. There's no way Venus can't be tidelocked to Earth.


Venus since it spins would also have a magnetic field.
Not hugely likely given the slow rotation period if tidelocked.
 
Originally posted by Malenfant:
OK, "Venus" is still able to orbit Earth at a distance of 1.3 million km. JUST. 200,000 km more and it's beyond Earth's Hill Sphere, and it orbits the sun instead.
How about a different way to get a similar result: Move "Venus" out those 200kkm and let it orbit the sun again.

Would that work? How close could two planets, which independently orbit the sun, be? Could they be close enough to both fit into the life zone?
 
*GAH*

*reaches through the computer and strangles half the respondees*

I beleive the question asked was not "is Venus tidally locked to the Earth in this situation", nor was it "How is Evolution altered by this situation"... it was:
"Now I ask the audience, how would you design such a mission? Would you have more than 3 astronauts onboard? Since the mission does not call for a return to Earth, the additional mass that would otherwise be used for the return stages can be devoted instead to the landing capsule. What would you bring, keeping it limited to TL 7 of course?"

Accept the handwaving and just go with it.


Me?
Since it's a one way trip, my first thought was to use the mass freed up by not making the return trip and use it to bring the wives of Neil Armstrong, Buzz Aldrin, and Michael Collins...as a colonization mission rather than an exploration mission...

I didn't get that far, though, before it took a turn for the "Oh, my! What an interesting Plot Twist *THAT* would be..."

Both "our" Neil Armstrong and Buzz Aldrin divorced their wives *after* the Apollo 11 mission...wonder what happened to *their* Mr. and Mrs. Armstrong and Aldrin...
 
Yep Tom is looking for a fun scenario for an alternate history while Mal and some would like to see that such a scenario remain in the realm of plausible sci-fiction rather than impossible sci-fantasy. I see no problem with such input, it's offered as help I think, but agree the main thrust should be scenario. That is what Tom is interested in.

On the scenario side I agree, my first thought was two people is not nearly enough and not a good mix imo but it is at least workable if I recall my human dynamics right, a married couple might be the best in this case, if it's a "good" marriage, a family might even be better. Lost in Space ring some bells
Three people is worse for long term isolation, creates majority rule frictions, again iirc. A small colony idea might be doable, perhaps through more than one mission. And then after a few ships of settlers have arrived and just when the colony is looking good, overnight it vanishes. At least all the people do. The colony itself is still there from observation but no signs of life or bodies. Just like everyone went to bed and vanished in their sleep without a trace. Will the US send an investigation team? What will they find? Was it the Russians? Did they beat the US there afterall and in secret? Or is there something else on Venus? Tune in next week for the continuing adventures of Fort Venus!
 
Actually the idea for the scenario that hit me when Tom posted, to fit his idea of an Earth like planet handy for astronauts was to borrow from the movie Journey to the Far Side of the Sun with a couple changes of course.

First, no silly mirror reverse idiocy


Second, no closely parallel biology and development. Give Earth it's Moon and the same progress up till the first rocket launches. Then have the discovery of the second planet.

Of course I'd want Mal's (or some other expert) on the validity of a second planet of like size and composition being in the same orbit and it being stable for both. Not the probability of such, just the is it possible. I'm also not sure how hard it would be to detect such a planet by orbital observations from the ground. Would there be clues to the other body in it's influence on any other orbits and how early would such be detectable by men of science and math?

Anyway, in this scenario you'd might have a sudden diversion of resources from the "go to the moon and do this..." to an investigation of and race for this other earth. Just an idea to add to the possibles.
 
Originally posted by daryen:
How about a different way to get a similar result: Move "Venus" out those 200kkm and let it orbit the sun again.

Would that work? How close could two planets, which independently orbit the sun, be? Could they be close enough to both fit into the life zone? [/QB]
Honestly? I don't know. I would however suspect that something odd would end up happening - either one planet gets flung out of the system by the interactions between the two, or the two planets would likely end up in some stable orbital resonance where one ends up in the same place relative to the other after X number of orbits of the inner planet and Y orbits of the outer planet (where X:Y could be 1:2 or 2:3 or 3:4). And the inner planet would be 180 degrees around the the orbit from the outer one when they came back to the same place relative to eachother. That'd be a stable resonance.

As it is, IIRC Venus and Earth ARE actually in a weird orbital resonance. Venus completes five rotations around its axis between one closest approach to Earth and the next (which means we end up seeing the same face at closest approach).
 
So what Mal is saying is that the Earth is on the Edge of a tidal lock. That is if the Moon were just a tiny amount more massive, the Earth's rotation would suddenly stop. Excuse me if I sound a tad skeptical, but just because something's written in a book doesn't mean its true. We don't have planets to experiment with to confirm the validity of the equations you speak of. I'll assume that no one really knows and leave the situation as is. The assumptions used in those equations might be wrong. Other Solar Dynamics equations have been wrong before, so who's to say they won't be proved wrong in the future? Anyway its easier to imagine two planets forming in mutual orbit about each other rather than both in the same orbit, but not orbiting each other.
Lets just have some suspention of disbelief with regards tothe tidal effects for now and agree to disagree with Malenfant. The point is I got this globe of Venus and I'd like to use it for something. There, now lets move on shall we.

Piper said,
Are you envisioning totally alien life forms or ones basically similar to those here with cosmetic differences?

Even starting with the same genetic stock you have a lot of room for diversity. A different ending to Earth's Cambrian period might have produced radically different life here.

Check out info on the Burgess Shale if you're not already familiar with it.
And depending on which (if any) extinction theories you follow, you could use our bio-history and move it several million years in either direction.
--------------------------------------------------------------------------------
On a cellular level Venusian Life is similar to Earth life. Certain basic life forms have evolved parallel to Earth. There are plants, trees, grasses, moss, and algae in the oceans, the specific kinds of these plants are completely alien, although certian trees have leaves which they lose in the winter, while other types retain their photosythetic collectors through winter.
In the animal kingdom their are invertibrates and vertibrates. In the oceans their are various kinds of fishes that extract oxygen from the water. On land their are multilegged creatures similar to insects. Most of the larger land creatures are 4-legged vertibrates, some are warm blooded others are cold blooded, some lay eggs, others bear young live, some fly, others climbs trees, still others live underground. Venus has examples of creatures that tend to be larger than the largest specimin of land dwelling Earth creatures now living, and some of these creatures can be a danger to Earth Humans. Humans can eat some of the animals and plants and derive some nutrition from them and the same applies to animals eating humans. Many trees have wooden stems to support their tremendous heights. The trees tend to be substantially taller than the typical trees in Earth Forests, this is mostly because there has been no logging activity until the arrival of Earth humans. It is entirely possible for humans to live off the land indefinitely through hunting and gathering activities, although the shapes of the plants and animals are completely unfamiliar.

Is there intelligent life? Maybe. I haven't decided yet. Depends whether the animals and competing nations will generate sufficient adventure or not, so we'll leave that possibility open. There doesn't appear to have been a civilization on Venus in recent times, although something might be discovered in the jungles.
 
Originally posted by Tom Kalbfus:
[QB] So what Mal is saying is that the Earth is on the Edge of a tidal lock. That is if the Moon were just a tiny amount more massive, the Earth's rotation would suddenly stop.
Wow, so you don't read a word anyone says in any subject then (not just politics)? I'm starting to think you have serious reading comprehension problems, because I didn't say that at all and I also didn't even remotely imply that either.

FYI, Venus is more than 'a tiny amount more massive than the moon'. It's about 66 times more massive. That makes a hell of a lot of distance, even if it's further out than the moon current is.

Secondly, you don't figure out tidal forces by comparing gravitational field strength at that distance as you did. It's a hell of a lot more complicated than that.

I could explain more, but I suspect I'd be wasting my time given your attitude.
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Excuse me if I sound a tad skeptical, but just because something's written in a book doesn't mean its true.
If it's in the authoritative science book on the subject then damn straight it's true (or rather, it's "accurate given our current understanding of the subject, which is pretty damn good"). The numbers I threw at you aren't wrong, given the data we have and the well proven theories and observations we have (which are very well developed indeed).

And bottom line, Tom? I know what I'm talking about - you don't.


We don't have planets to experiment with to confirm the validity of the equations you speak of.
Er, we have 9 planets and a few hundred moons, actually. Plus a hell of a lot of double stars and multiple systems. Trust me, the equations are confirmed.


I'll assume that no one really knows and leave the situation as is. The assumptions used in those equations might be wrong. Other Solar Dynamics equations have been wrong before, so who's to say they won't be proved wrong in the future? Anyway its easier to imagine two planets forming in mutual orbit about each other rather than both in the same orbit, but not orbiting each other.
Let me put it this way, Tom. I know a hell of a lot about this subject - I did my PhD on it. You on the other hand, know very little. If you want to learn more about it, then listen to what I tell you. If you don't want to learn more about that, then thank me for my time and I'll leave you to it, I'm fine with that. But don't give me crap about how the books and the science are probably wrong just because reality doesn't work how you think it does.
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:mad:

Despite my opinion of you I decided I'd waste my time last night figuring stuff out for your little question here, because it was an interesting thought experiment. The least you could do is be grateful for that, even if it turns out you don't need or want it.
 
Dr. Thomas,

Leaving Mr. Kalbfus, Earth, and Venus aside for a moment...

You neatly 'solved' Antares for Paul Drye. Can you also 'solve' a habitable pair of tidally locked planets for the rest of us?

H. Beam Piper's First Cycle featured two Earth-like tidally locked planets revolving around a common point while sharing the same orbit. The length of day/night cycles didn't seem to be a problem for the pair either. Is this possible, probable, or utter nonsense?

Inquiring minds want to know.


Thanks in advance,
Bill
 
Originally posted by Bill Cameron:
[QB]You neatly 'solved' Antares for Paul Drye.
Well, "solved" being "discovered that if it went boom then it'd wipe out pretty much everything within a hundred parsecs at least... not the ideal solution really, bit of a setting-changer ;) .


Can you also 'solve' a habitable pair of tidally locked planets for the rest of us?

H. Beam Piper's First Cycle featured two Earth-like tidally locked planets revolving around a common point while sharing the same orbit. The length of day/night cycles didn't seem to be a problem for the pair either. Is this possible, probable, or utter nonsense?
The problem really is the sun, because the tidal force from that is quite strong and will affect the system (it sucks angular momentum out of the binary once they're tidelocked to eachother, which means the two planets converge and crash into eachother)

If they're close enough to eachother for them to both be tidelocked and have a 24 hour long day/orbital period then they are going to be very close and the distortion due to tides will be extreme (atmosphere and solid rocky body wil be egg-shaped, never mind the oceans), and the whole situation wouldn't be stable given the solar tides.

It might work in the outer reaches of the solar system though - far from the sun or any other massive bodies (like Pluto/Charon is), but then your planets won't be habitable - they'd be big iceballs (with less mass to mitigate the tidal distortion issue too). But close to the sun (ie in the habitable zone)? I don't think it could work at all.
 
Originally posted by Malenfant:
[Well, "solved" being "discovered that if it went boom then it'd wipe out pretty much everything within a hundred parsecs at least... not the ideal solution really, bit of a setting-changer.
Dr. Thomas,

No, I was thinking more as 'solved' as in 'found a way to stick a habitable planet in a system that shouldn't really have one'. As in the brown dwarf companion orbited by the canonical Antares mainworld remember?


The problem really is the sun, because the tidal force from that is quite strong and will affect the system (it sucks angular momentum out of the binary once they're tidelocked to each other, which means the two planets converge and crash into each other)
But close to the sun (ie in the habitable zone)? I don't think it could work at all.
Okay, thanks! The planetary system described in First Cycle has now joined Burrough's Barsoom in my science fantasy catagory. Don't get me wrong. I still like both stories, I've just pushed them further down the probabilty scale is all.


Have fun,
Bill
 
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